/*
 * Copied from the following location:
 * http://apps-for-android.googlecode.com/svn-history/r93/trunk/DivideAndConquer/src/com/google/android/divideandconquer/Eula.java
 * 
 * Copyright (C) 2008 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package bankdroid.soda;

import java.io.BufferedReader;
import java.io.Closeable;
import java.io.IOException;
import java.io.InputStreamReader;

import android.app.Activity;
import android.app.AlertDialog;
import android.content.DialogInterface;
import android.content.SharedPreferences;
import bankdroid.util.AppId;

/**
 * Displays an EULA ("End User License Agreement") that the user has to accept before
 * using the application. Your application should call {@link Eula#show(android.app.Activity)}
 * in the onCreate() method of the first activity. If the user accepts the EULA, it will never
 * be shown again. If the user refuses, {@link android.app.Activity#finish()} is invoked
 * on your activity.
 */
class Eula
{
	public static final String ASSET_EULA = "EULA";
	public static final String PREFERENCE_EULA_ACCEPTED = "eula.accepted";
	public static final String PREFERENCES_EULA = "eula";

	/**
	 * callback to let the activity know when the user has accepted the EULA.
	 */
	static interface OnEulaAgreedTo
	{

		/**
		 * Called when the user has accepted the eula and the dialog closes.
		 */
		void onEulaAgreedTo();
	}

	/**
	 * Displays the EULA if necessary. This method should be called from the onCreate()
	 * method of your main Activity.
	 *
	 * @param activity The Activity to finish if the user rejects the EULA.
	 * @return Whether the user has agreed already.
	 */
	static boolean show( final Activity activity )
	{
		AppId.getAppId(activity); // init app Id

		final SharedPreferences preferences = activity.getSharedPreferences(PREFERENCES_EULA, Activity.MODE_PRIVATE);
		if ( !preferences.getBoolean(PREFERENCE_EULA_ACCEPTED, false) )
		{
			final AlertDialog.Builder builder = new AlertDialog.Builder(activity);
			builder.setTitle(R.string.eula_title);
			builder.setCancelable(true);
			builder.setPositiveButton(R.string.eula_accept, new DialogInterface.OnClickListener()
			{
				public void onClick( final DialogInterface dialog, final int which )
				{
					accept(preferences);
					if ( activity instanceof OnEulaAgreedTo )
					{
						( (OnEulaAgreedTo) activity ).onEulaAgreedTo();
					}
				}
			});
			builder.setNegativeButton(R.string.eula_refuse, new DialogInterface.OnClickListener()
			{
				public void onClick( final DialogInterface dialog, final int which )
				{
					refuse(activity);
				}
			});
			builder.setOnCancelListener(new DialogInterface.OnCancelListener()
			{
				public void onCancel( final DialogInterface dialog )
				{
					refuse(activity);
				}
			});
			builder.setMessage(readEula(activity));
			builder.create().show();
			return false;
		}
		return true;
	}

	private static void accept( final SharedPreferences preferences )
	{
		preferences.edit().putBoolean(PREFERENCE_EULA_ACCEPTED, true).commit();
	}

	private static void refuse( final Activity activity )
	{
		activity.finish();
	}

	private static CharSequence readEula( final Activity activity )
	{
		BufferedReader in = null;
		try
		{
			in = new BufferedReader(new InputStreamReader(activity.getAssets().open(ASSET_EULA)));
			String line;
			final StringBuilder buffer = new StringBuilder();
			while ( ( line = in.readLine() ) != null )
				buffer.append(line).append('\n');
			return buffer;
		}
		catch ( final IOException e )
		{
			return "";
		}
		finally
		{
			closeStream(in);
		}
	}

	/**
	 * Closes the specified stream.
	 *
	 * @param stream The stream to close.
	 */
	private static void closeStream( final Closeable stream )
	{
		if ( stream != null )
		{
			try
			{
				stream.close();
			}
			catch ( final IOException e )
			{
				// Ignore
			}
		}
	}
}